A silicon carbide (SiC) is highly expected as a semiconductor material for next-generation power devices and high-frequency devices that achieves a high-temperature resistance, high frequency resistance, high voltage resistance and high environmental resistance, which cannot be achieved by the existing semiconductor materials such as silicon (Si) or gallium arsenide (GaAs).
Patent Document 1 discloses a heat treatment container used for an etching treatment of this kind of disc-shaped SiC substrate. The heat treatment container has a plurality of spacers between a disc-shaped single crystal SiC substrate and an inner bottom surface of the heat treatment container. The SiC substrate is supported by the spacers. In such configuration, both main surfaces of the SiC substrate (an upper surface and a lower surface, Si-face and C-face) are sufficiently exposed to an internal space of the heat treatment container, and the etching treatment is performed on both of the main surfaces by performing the heat treatment of the SiC substrate under Si vapor pressure.